1. Field of the Invention
The present invention relates to apparatuses, methods, and systems for wireless communication. More particularly, the present invention is related to a communication apparatus, method and system that make corrections for burst error in reducing bias of a signal level.
2. Description of Related Art
In wireless communication, there has recently been a growing demand to increase transmission speed in order to achieve real-time transmission and reception of rich contents such as moving images and seamless connection to wired communication. For implementation of such high-speed high-capacity data communication, there are great expectations for a millimeter wave wireless communication technique intended to achieve high-speed wireless communication exceeding a Gbps level.
A wireless communication apparatus typically includes a digital processing section (baseband) responsible exclusively for digital signal processing and an analog processing section (RF: Radio Frequency) responsible exclusively for analog signal processing. These circuit blocks are typically interconnected by AC coupling (capacitive coupling) in order to absorb a difference in I/O bias voltage and to achieve a stable operation.
The AC coupling needs to keep a DC balance, and the presence of a large number of DC components and low-frequency components makes accurate data transmission difficult. A bias of bits in a transmission signal results in a DC offset component, and thus, a preprocess is typically carried out using a scrambler or a data coding technique to sufficiently diffuse transmission bits to prevent the bits from being biased. Examples of the data coding include 8b10b coding, bit stuffing as discussed in S. Aviran, et. al, “An Improvement to the Bit Stuffing Algorithm”, IEEE Trans. Inform. Theory, Vol. 51, pp 2885-2891, 2004, and Fibonacci coding as discussed in A. S. Fraenkel, et. al, “Robust Universal Complete Codes for Transmission and Compression”, Discrete Applied Mathematics, vol. 64, pp 31-55, 1996.
However, the above-decried data coding techniques insert additional bits, and thus, coding efficiency decreases in return. On the other hand, the sole scrambler apparently uniformly diffuses the bits but may cause a bias as a result of the scrambling, which may in turn increase an error rate.
On the other hand, the wireless communication assumes data transmission in an environment with a lower signal to noise ratio (SNR) than the wired communication, and thus involves a powerful error correcting code also in accordance with wireless communication standards. The error correcting code enables sporadic, single- or double-bit random errors to be efficiently corrected.
However, a typical error correcting code may fail to completely correct a burst error in which a large number of errors concentrate in a short interval. Errors caused by the above-described DC offset occur consecutively once the DC offset reaches a specific value or larger, resulting in a burst error. This conventionally is a factor that significantly reduces an effective transmission rate. In other cases, the burst error leads to the need to increase a circuit scale and power consumption in order to achieve more powerful error correction.
Thus, a novel technique has still been desired to be developed which enables suitable prevention of a burst error caused by a variation in reference level associated with coupling and observed on a reception apparatus side, without the need for insertion of additional bits such as coding.